Screening for CF carriers?

In the UK, about one in 25 people carries the altered gene that causes cystic fibrosis (CF). They are unaffected by the condition, and most will never know they are carriers. But if two carriers have children, each child has a one-in-four chance of inheriting two altered genes and being born with CF. Doctors sometimes offer tests to identify carrier couples, to help them make decisions when planning a pregnancy. But there are many versions (alleles) of the altered gene involved, and tests cannot identify them all.

Couples who are both carriers of cystic fibrosis are offered genetic counselling.